Apparatus for soil compaction

ABSTRACT

An apparatus for soil compaction, such as a vibration tamper, comprises a substructure having a tamper foot and a bottom guide cylinder arranged thereon, and a superstructure having a housing, an upper guide cylinder arranged thereon and at least one drive unit which is in operative connection via a drive train with the tamper foot in the substructure in such a way that it can be moved relative to the superstructure along at least one compaction axis (A v ) with at least one compaction amplitude (a), with at least one stop element being arranged between the superstructure and the substructure, which stop element will stop the movement of the substructure relative to the superstructure upon exceeding a maximum compaction amplitude (a max ).

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. §119 of German Patent Application No. 10 2010 046 820.7, filed Sep. 28, 2010, the disclosure of which is hereby incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to an apparatus for soil compaction and especially a vibration tamper with a substructure, comprising a tamper foot and a bottom guide cylinder arranged thereon, and a superstructure, comprising a housing, an upper guide cylinder arranged thereon and at least one drive unit which is in operative connection via a drive train with the tamper foot in the substructure in such a way that it can be moved relative to the superstructure along at least one compaction axis with at least one compaction amplitude, with the upper guide cylinder and the bottom guide cylinder being movable relative to one another in the direction of the compaction axis by forming at least one axial guide.

BACKGROUND OF THE INVENTION

Such soil compaction apparatuses are known from the state of the art. They are usually arranged in such a way that a tamper foot arranged in a substructure and especially a tamper plate can be driven to oscillating axial movements by way of a drive apparatus in a superstructure of the tamper in order to introduce compacting load pulses into the subsoil.

The motor is mostly in connection with the tamper foot by way of an eccentric drive, with the eccentric drive being in operative connection with a drive train which converts the mechanical work of the motor into an axial movement of the drive train and the tamper foot which is coupled thereto.

In order to enable the free axial movement of the tamper foot, a spring assembly arranged in a guide cylinder is usually arranged at the free end of the connecting rod in the region of substructure, which spring assembly enables an axial oscillating movement of the tamper foot.

Such a vibration tamper is known from U.S. Pat. No. 3,090,286. It comprises a motor, with an eccentric gearwheel being arranged on its rotating output shaft. The eccentric gearwheel is in operative connection with a sliding block with a link of a connecting rod, so that the rotational movement of the motor can be converted into an axial movement of the connecting rod and therefore the entire drive train of the vibration tamper.

The connecting rod comprises a guide piston at its free end, which guide piston can be moved axially in a reciprocating manner by way of a piston guide within a bottom guide cylinder belonging to the substructure. This axial direction corresponds to the compaction motion during the compaction operation. A spring assembly consisting of one or several springs is arranged axially on both sides of the piston guide, with the springs respectively being supported against spring plates fastened to the bottom guide cylinder on their sides facing away from the piston guide. The bottom guide cylinder engages into a plain slideway in an upper guide cylinder which is rigidly connected with the housing of the vibration tamper.

Driven by the oscillating drive train, the bottom guide cylinder moves in the axial direction together with the tamper foot connected thereto or a tamper plate in compacting operation, with the maximum compacting amplitude in compacting operation being defined among other things by the employed spring assembly, the relative play of the upper and bottom guide cylinder and the size of the eccentric drive. A vibration tamper with good compacting performance is thereby obtained in combination with sufficient dimensioning.

It may occur, however, that the vibration tamper will fall onto the tamper foot with its full weight during unloading from a truck, for example. The result is a motion of substructure or the tamping foot towards the superstructure, as also occurs in compacting operation. It may occur depending on the dropping impulse that the movement amplitude introduced by the substructure relative to the superstructure is larger than would be the case in normal compacting operation. In such a case, however, the drop energy will be introduced by way of the drive train of the vibration tamper into the gearing device or the drive device. This may lead to serious damage.

For this reason, the configurations of the gear bearings in vibration tampers as known from the state of the art are provided with very large dimensions for this reason. This has negative effects on the weight of the machine and the weight distribution of the entire machine.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a vibration tamper of the kind mentioned above which, in combination with a lighter and more cost-effective configuration, is better protected from damage, especially during transport.

This object is achieved by an apparatus for soil compaction and especially a vibration tamper, comprising a substructure having a tamper foot and a bottom guide cylinder arranged thereon, and a superstructure having a housing, an upper guide cylinder arranged thereon and at least one drive unit which is in operative connection with the tamper foot in the substructure by way of a drive train in such a way that it can be moved relative to the superstructure along at least one compaction axis with at least one compaction amplitude, with the upper guide cylinder and the bottom guide cylinder being movable by forming at least one axial guide relative to one another in the direction of the compaction axis, and with at least one stop element being arranged between the superstructure and the substructure, which stop element will stop the movement of the substructure relative to the superstructure upon exceeding a maximum compaction amplitude.

The guide cylinder shall be understood within the scope of the present invention as being any component which can be used for guidance between the superstructure and the substructure and/or the guidance of a drive train arranged in the interior of the guide cylinder and especially a connecting rod with a spring cartridge or spring assembly. This means that the guide cylinder can therefore not only have the geometrical shape of a cylinder, but also any other shape. Amplitude shall be understood in this connection as being any maximal movement or maximal deflection in a direction of the compaction axis as occurs during the drive of tamper feet by way of eccentric drives.

The stop element concerns an element in accordance with the present invention which, during a relative movement between the superstructure and substrate, acts in an arresting manner on the degree of freedom of movement once the relative movement has a high amplitude than is the case during compacting operation, or if such a movement amplitude is larger than a so-called maximum compaction amplitude.

Compaction amplitude shall be understood in this case as being substantially the two maximum deflections which are carried out by the superstructure and substructure relative to one another during compacting operation. If, therefore, a tamper foot oscillates outwardly and inwardly relative to the superstructure during compacting operation, the compaction amplitude corresponds to half the distance between the completely inwardly oscillated state and completely outwardly oscillated state, i.e., half the value from tip to tip.

Once this compaction amplitude is exceeded, e.g., by dropping the vibration tamper onto the tamper foot, which means that the tamper foot moves towards the superstructure beyond the amplitude which is usually provided during the compaction operation, the stop element between the superstructure and the substructure will act, so that the movement of the substructure relative to the superstructure will be arrested and especially a discharge of forces by the drive train into the drive unit caused by the dropping will be prevented.

Such a case in which the stop element will arrest the relative movement between the superstructure and the substructure will be referred to within the scope of the present invention as a limit stop case.

Since the dissipation of the load in the limit stop case will not occur by way of the drive train, etc., the drive train and the gear parts can be provided with a smaller dimension among other things, which means that the weight of the machine will be reduced advantageously.

The above application also applies to an embodiment in which a respective excessive spring deflection of the substructure from the superstructure is to be prevented. In such a case, the stop element can also be used to prevent this.

The stop element and the two guide cylinders which can be moved towards one another are preferably arranged in such a way that the limit stop case will only occur when the normal compaction amplitude present during the compaction operation is exceeded by a safety value. If therefore the substructure moves in relation to the superstructure, for example, by a compaction amplitude of 20 cm, for example, the stop element will preferably spring into action when the “stop amplitude” would be more than 30 cm. This means, therefore, that in such a case the substructure is able to move towards the superstructure by a maximum amount of 30 cm before the stop element would stop this movement because the maximum compaction amplitude has been reached.

An embodiment which is advantageous concerning the geometry of the soil compaction apparatus comprises a stop element which is configured and arranged in such a way that upon exceeding the maximum compaction amplitude it is pressed against the housing and/or the upper guide cylinder. Loads introduced via the bottom guide cylinder, e.g., when the vibration tamper drops onto the tamper foot, will be dissipated in this manner via the upper guide cylinder and/or the housing without any damage to the drive device, the drive train and the gear device.

In order to achieve a dissipation of loads with the lowest possible damage and especially a stop of the movement, the stop element is preferably arranged as an elastic stop element. All embodiments known from the state of the art for stop and damping elements in particular can be used in this case. In particular, the stop element can be arranged as a rubber buffer which is arranged between the components that move relative to one another and especially the upper and the bottom guide cylinder or the housing.

In order to secure the position of the stop element especially in the direction of the compaction axis, the stop element comprises at least one fastening element, by means of which it is held in a substantially stationary manner on the superstructure or substructure. As a result, the acceleration load acting especially on the stop element during the compaction operation or obviously also during the limit stop case will be absorbed. Such a fastening element can also be an interlocking or friction-locking element. It is, therefore, possible to provide at least one fastening groove or a similarly effective receiving element on the stop element, into which at least one complementarily arranged projecting element on the superstructure or substructure will engage in a locking manner, or vice versa. The stop element can also be fastened by way of suitable interlocking or frictional engagement or press fit to the superstructure or substructure. This applies especially to elastic stop elements. In particular, it is also possible to use friction-locking elements as fastening elements. Such a fastening element can also be a locking screw which fastens the fastening element to suitable components on the superstructure or substructure.

One embodiment is advantageous from a constructional standpoint in which the stop element is held in a substantially stationary manner orthogonally to the compaction axis by the upper guide cylinder or the bottom guide cylinder. The upper or bottom guide cylinder is used in such s case at least as an axial guide for the stop element.

The stop element preferably comprises a stop sleeve or a similar ring element especially in an embodiment in which the drive train is guided within the upper guide cylinder and the bottom guide cylinder, which element encloses the drive train at least partially. This ensures securing the position of the stop element on the upper or bottom guide cylinder on the one hand, and ensures on the other hand the compact positioning of the stop element which is especially secured against mechanical loads.

In another embodiment in which the guide cylinders are positioned relative to one another in an axial plain slideway, with the bottom guide cylinder forming an inside guide and the upper guide cylinder forming an outside guide or vice versa, the stop element comprises at least one stop sleeve which is placed over the inside guide and comes into operative engagement with a stop region on the outside guide and/or a stop region on the inside guide at least when exceeding the maximum compaction amplitude and stopping the relative movement between the inside guide and the outside guide.

Such an axial plain slideway between the upper and the bottom guide cylinder can be arranged by an embodiment with an inside guide disposed at the bottom and an outside guide disposed at the top and also by an outside guide disposed at the bottom and an inside guide disposed at the top. This is referred to by the aforementioned passage “or vice versa”.

It is principally possible in such a “telescopic” guide cylinder to arrange the stop element in form of a stop sleeve between the two guides, so that they come into operative engagement by stop regions arranged on the respective guides by way of the interposed stop element and thereby stop the relative movement towards one another or also away from one another. Fastening of the stop element is enabled here among other things by way of frictional locking.

Notice must be taken especially in this connection that principally the stop element can obviously not only be arranged in such a way that it stops the movement of the substructure towards the superstructure, but it also stops a movement of the substructure away from the superstructure in order to prevent damage to the drive train etc by excessive tensile loads. In the former case, the stop element is loaded as a pressure element and in the second case as a tensioning element.

The stop sleeve can be arranged in such a way that it is in a press fit with the bottom or the upper guide cylinder and is thereby held in a stationary manner in the axial direction and/or in a direction which is orthogonally thereto. It is also possible to provide suitable bearing or locking means on the outside guide or inside guide stop regions, which means allow fixing the stop element at least to one of these stop regions. The inside guide stop region can be provided with a locking groove, for example, in which the stop element or its stop sleeve can engage with a suitable locking projection. All locking means can principally be applied in this case in order to fix the stop element or its stop sleeve to the outside guide stop region or the inside guide stop region.

In order to achieve an especially effective bearing of stop sleeve on the guide cylinder, it preferably comprises suitable set-offs, on which the stop element rests with projections that are arranged in a complementary manner, or vice versa. As a result, force will be transmitted between the bottom guide cylinder and the upper guide cylinder or the housing in the limit stop case over the entire length of the stop element.

The guide element is provided with reinforcements especially in pressing regions in which the stop element comes into contact with the outside guide stop regions and/or the inside guide stop regions, which reinforcements ensure non-positive contact and secure dissipation of the load.

In the case of a stop element which is arranged on the inside guide and especially on an outside jacket of the inside guide and especially in the case of a stop element arranged as a stop sleeve, the complementary outside guide stop region is preferably arranged on a face side region of the outside guide. This means that the stop element arranged on the inside guide will rest against the face side region of the outside guide upon exceeding the maximum compaction amplitude and will thereby stop the relative movement between the outside guide and the inside guide.

In the case of another embodiment, in which the guide cylinders are disposed relative to one another in an axial plain slideway, with the bottom guide cylinder forming an inside guide and the upper guide cylinder forming an outside guide or vice versa, the stop element is arranged within the outside guide, so that upon exceeding the maximum compaction amplitude it will come into an operative engagement in a stopping manner with an inside guide stop region on the inside guide and therefore stop the relative movement between the inside guide and the outside guide. In such a case, the inside guide stop region is preferably arranged on a face side region of the inside guide.

In the above embodiment, the stop element is preferably arranged to be completely mechanically protected within the outside guide and is positioned especially in permanent contact with the housing, so that upon exceeding the maximum compaction amplitude the inside guide stop region will meet the stop element and will thereby stop the relative movement between the upper and the bottom guide cylinder, with the resulting forces being diverted directly into the housing.

It is not only possible in such a case to arrange the stop element as a stop disk which is arranged in a complementary manner in relation to the inside geometry of the outside guide and which comprises a lead-through opening for the drive train especially in a centric manner. As a result, the stop element is guided through the inside wall of the outside guide and/or through the drive train extending in a centric manner. In particular, the stop element can be used in such an embodiment to prevent buckling of the drive train and especially a connecting rod perpendicularly to the tamping axis. Respective stabilizing elements can be provided in the stop element, for example. It is also possible to provide the stop element with suitable bearing means in the region of the lead-through for the drive train.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be described below by reference to two embodiments which will be explained in closer detail by reference to the schematic drawings, wherein:

FIG. 1 shows a longitudinal sectional view through an embodiment of the apparatus in accordance with the present invention for soil compaction; and

FIG. 2 shows a detailed view of a longitudinal sectional view according to FIG. 1 of a second embodiment of the apparatus for soil compaction.

The same reference numerals will be used below for the same and similarly acting components, with superscript indexes being used occasionally for differentiation purposes.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a longitudinal sectional view through an embodiment of the apparatus for soil compaction in accordance with the present invention and especially a vibration tamper 1. The vibration tamper 1 comprises a superstructure 8 and a substructure 2 which are movable relative to one another. This movement is guided by way of an upper guide cylinder 12 which is in axial sliding connection with a bottom guide cylinder 6 coaxially to the compaction axis A_(v). The upper guide cylinder 12 is arranged in a stationary manner on a housing 10 of the superstructure 8, whereas the bottom guide cylinder 6 is connected in a stationary manner with a tamper plate 5 and forms a tamper foot 4. The two guide cylinders 6, 12 are movable relative to one another in such a way that a tamping movement for soil compaction can be performed within the scope of a compaction amplitude a along the compaction axis AV.

In this embodiment, the upper guide cylinder 12 forms an outside guide into which or out of which the bottom guide cylinder 6 in form of an inside guide will slide in a telescopic manner. The inside guide 6 and the outside guide 12 jointly form an axial guide 18 for the tamper foot 4 and the drive train 16 arranged in the interior.

In order to protect the upper and bottom guide cylinder 6, 7 which are disposed in a plain slideway with each other from mechanical jolts and especially from dust, a bellows 30 is arranged on the outside which encloses the two guide cylinders 6, 12.

The vibration tamper 1 is driven by way of a drive unit 14 which is held in the superstructure and especially in the housing 10 and which is in operative connection with the tamper foot 4 via the drive train 16.

The drive unit 14 comprises a motor 3 which converts the rotational movement of the motor into an axial movement of a connecting rod 38 of the drive train 16 along the compaction axis A_(v) via an output shaft 19 with a gear unit 15 and especially an eccentric drive 34. The connecting rod 38 ends in a piston guide 13 which is axially guided in the interior of the bottom guide cylinder 6 along the compaction axis A_(v).

A spring assembly 17 is connected to the piston guide 13, which spring assembly connects the piston guide 13 in a resilient manner with the bottom guide cylinder 6 and thereby allows a resilient axial movement of the tamper plate 5 or the tamper foot 4 along the compaction axis A_(v).

During the compaction operation, the tamper foot 4 or the tamper plate 5 oscillates back and forth about the amplitude a indicated here between the zero position shown here (characterized by the reference numeral 40) and a maximum deflection (characterized by the reference numeral 42).

As soon as a load acts on the tamper foot 4 which moves it from the position as shown in FIG. 1 further in the direction of the superstructure, there is a likelihood that loads need to be dissipated by way of the drive train 16 and the transmission unit 15.

For this reason, a stop element 20 is arranged in the interior space 21 of the upper guide cylinder 12 or outside guide 12, which stop element will stop the movement of the bottom guide cylinder 6 or inside guide 6 towards the superstructure 8 when a maximum movement amplitude a_(max) is exceeded.

This stop element 20 is arranged in such a way that upon exceeding the maximum amplitude a_(max) it will come into operative engagement with an inside guide stop region 36 of the inside guide 6 and will transmit the loads introduced into the inside guide stop region 36 to the housing 10. The inside guide stop region 36 is arranged in this embodiment on the face side region 28 of the inside guide 6.

It can be seen that in this embodiment there is a difference between the “normal” compaction amplitude a and the maximum compaction amplitude a_(max), and there is especially a securing range b which will only allow impingement on the stop element 20 only when the compaction amplitude a is significantly exceeded by the value b. This securing range takes into account the oscillating movement via the spring assembly 17 among other things.

The stop element 20 is arranged in this embodiment in such a way that it is in a press fit with the inside wall 11 of the outside guide 12. Moreover, a receiving region 23 is provided on the inside wall 11 which is arranged in a complementary manner in relation to the stop element 20 and thereby ensures bearing of the stop element 20 both orthogonally to the compaction axis A_(v) and also coaxially thereto.

The upper guide cylinder 12 is arranged in such a way that it laterally fixes the stop element 20, whereas axial forces, which are introduced by the inside guide stop region 36 of the bottom guide cylinder 6, are transmitted directly into the housing 10 or an outside guide stop region 32.

In summary, the oscillating movement of the vibration tamper 1 is as follows: the position of the tamper foot 4 as shown in FIG. 1 corresponds to the maximally lifted position when viewing the tamper foot 4 statically, i.e., in a non-oscillating way. The similarly shown position 42 corresponds to the zero position in compaction operation. The deflection illustrated by way of the value a_(s) is obtained from the spring-elastic behavior of the spring assembly 17 which enables free oscillation of the tamper foot 4 relative to the superstructure 8, so that the tamper foot 4 will move towards the superstructure 8 with the compaction amplitude a. The similarly shown amplitude a_(max) corresponds to the amplitude which can be passed through maximally by the two guide cylinders 6, 12 before the stop element 20 suppresses this relative movement. This can be used, for example, for buffering the fall of the vibration cylinder 1 from a specific overall height. Once this maximum compaction amplitude a_(max) is exceeded especially during the compression of the substructure 2, the stop element will stop the compressing movement, so that especially the drive train 16 and the gear unit 15 need not dissipate any loads by this compression movement.

A securing range b is shown in addition to the amplitudes a_(s), a and the maximum amplitude a_(max), which securing range guarantees that impingement on the stop element 20 will not occur continually especially during material fatigue or imprecision in the components. Only when the compaction amplitude a is significantly exceeded by this range b will the stop element 20 stop the relative movement of the substructure 2 in relation to the superstructure 8.

FIG. 2 shows a further embodiment of a vibration tamper 1. Especially its substructure 2 is shown in a longitudinal sectional view according to the illustration of FIG. 1. In this case too, an upper guide cylinder 12 is in operative connection with a bottom guide cylinder 6 of the substructure 2 in an axial guide 18, so that a tamper foot 4 or a tamper plate 5 can be driven by way of a drive train 16, coaxially to the compaction axis A_(v) in a compacting movement. The bottom guide cylinder 6 forms the inside guide and the upper guide cylinder 12 forms the outside guide.

This embodiment also comprises a stop element 20 for stopping the movement of the tamper foot 4 or the inside guide 6 relative to the outside guide 12, which stop element is slid as a stop sleeve 24 onto the outside wall 25 of the bottom guide cylinder 6. Interlocking and friction-locking elements are used here as the fastening element 22. The stop sleeve 24 is arranged for this purpose complementary to the outside wall 25 of the inside guide in such a way that its position remains fixed by way of friction-locking in the axial direction of the compaction axis A_(v). This fixing is amplified by the elastic arrangement of the stop element.

The stop element 20 is arranged at the base region 7 of the tamper foot 4. It rests with an inside guide stop region 36 on the base area 7 of the tamper foot 4. The stop element 20 further comprises bearing projections 29 which rest on the inside guide 6 in complementarily arranged bearing set-offs 31.

The stop element 20 or its stop sleeve 24 is arranged in such a way that when the maximum amplitude a_(max) is exceeded and especially when an excessive compression of the tamper foot 4 occurs this movement is stopped by the operative engagement between the stop sleeve 24 and an outside guide stop region 32 on the outside guide 12. The outside guide stop region is arranged in this embodiment on the face side region 26 of the outside guide. In this respect, the functionality of this embodiment corresponds to the previously described functionality of the first embodiment.

The difference is that by positioning the stop element 20 on the outside wall 25 of the bottom guide cylinder 6 the introduction of forces occurs by way of the upper guide cylinder 12 or the outside guide 12 into the housing 10 when the maximum compaction amplitude a_(max) is exceeded. In this case too, the forces from exceeding the maximum amplitude a_(max) are not introduced into the drive train 16 or the gear unit, but are dissipated directly via the housing.

While the present invention has been illustrated by description of various embodiments and while those embodiments have been described in considerable detail, it is not the intention of Applicants to restrict or in any way limit the scope of the appended claims to such details. Additional advantages and modifications will readily appear to those skilled in the art. The present invention in its broader aspects is therefore not limited to the specific details and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of Applicants' invention. 

1. An apparatus for soil compaction, especially a vibration tamper, comprising: a substructure having a tamper foot and a bottom guide cylinder arranged thereon, and a superstructure having a housing, an upper guide cylinder arranged on the housing and at least one drive unit which is in operative connection via a drive train with the tamper foot in the substructure in such a way that it can be moved relative to the superstructure along at least one compaction axis (A_(v)) with at least one compaction amplitude (a), with the upper guide cylinder and the bottom guide cylinder being movable relative to one another in the direction of the compaction axis (A_(v)) by forming at least one axial guide, wherein at least one stop element is arranged between the superstructure and the substructure, which stop element will stop the movement of the substructure relative to the superstructure upon exceeding a maximum compaction amplitude (a_(max)).
 2. An apparatus according to claim 1, wherein the stop element is configured and arranged in such a way that upon exceeding the maximum compaction amplitude (a_(max)) it is pressed by the bottom guide cylinder against the housing and/or the upper guide cylinder.
 3. An apparatus according to claim 1, wherein the stop element is arranged as an elastic stop element.
 4. An apparatus according to claim 1, wherein the stop element comprises at least one fastening element, by means of which it is held in a substantially stationary manner on the superstructure or substructure in the direction of the compaction axis (A_(v)).
 5. An apparatus according to claim 1, wherein the stop element is held by the upper guide cylinder or the bottom guide cylinder in a substantially stationary manner orthogonally to the compaction axis (A_(v)).
 6. An apparatus according to claim 1, wherein the drive train is guided within the upper guide cylinder and the bottom guide cylinder, and wherein the stop element comprises a stop sleeve or a ring element which encloses the drive train at least partially.
 7. An apparatus according to claim 1, wherein the upper and bottom guide cylinders are positioned relative to one another in an axial plain slideway, with the bottom guide cylinder forming an inside guide and the upper guide cylinder forming an outside guide, or vice versa, and with the stop element comprising a stop sleeve which is placed over the inside guide and comes into operative engagement at least when exceeding the maximum compaction amplitude (a_(max)) with an outside guide stop region on the outside guide and/or an inside guide stop region on the inside guide by stopping the relative movement between the inside guide and the outside guide.
 8. An apparatus according to claim 1, wherein the outside guide stop region is arranged on a face side region of the outside guide.
 9. An apparatus according to claim 1, wherein the upper and bottom guide cylinders are positioned relative to one another in a plain slideway, with the bottom guide cylinder forming an inside guide and the upper guide cylinder forming an outside guide, or vice versa, and with the stop element being arranged within the outside guide and coming into operative engagement at least when exceeding the maximum compaction amplitude (a_(max)) with an inside guide stop region on the inside guide by stopping the relative movement between the inside guide and the outside guide.
 10. An apparatus according to claim 1, wherein the inside guide stop region is arranged on a face side region of the inside guide. 